Shenzhen Silver Star Intelligent Technology Co Ltd v. iRobot Corp

1. Case Identification

• Patent #: 8,474,090
• Filed: March 30, 2018
• Petitioner(s): Shenzhen Silver Star Intelligent Technology Co. Ltd
• Patent Owner(s): iRobot Corporation
• Challenged Claims: 1-11 and 17-19

2. Patent Overview

• Title: Floor Cleaning Robot
• Brief Description: The ’090 patent discloses an autonomous floor cleaning robot featuring wheels attached to the chassis via pivoting arms. The arms are biased by a spring mechanism to an extended position, but during operation, the robot's weight overcomes the spring force to press the wheels against the floor.

3. Grounds for Unpatentability

Ground 1: Claims 1, 5-11, and 17-18 are obvious over Kirkpatrick in view of WO ’744 and Allen.

• Prior Art Relied Upon: Kirkpatrick (Patent 6,481,515), WO ’744 (PCT application WO02067744A1), and Allen (Patent 5,995,884).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kirkpatrick taught the foundational autonomous mobile robot, including a housing, chassis, drive system, control module, and sensors. Kirkpatrick’s motor-gearbox assembly, which pivots relative to the chassis and has a resilient element, was asserted to function as the claimed "arm" and "spring." WO ’744 was introduced to explicitly teach a self-adjusting wheel support arrangement where the robot's weight overcomes a spring force, ensuring the wheels remain in contact with the floor, directly mapping to the weight-biasing limitation of claim 1. Allen was cited to teach a removable dust bag, which Petitioner argued renders the claimed "removable bin" obvious.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would be motivated to improve the suspension and particulate-handling capabilities of Kirkpatrick's robot. A POSITA would look to related art like WO ’744 for a more robust suspension system and to Allen for a more user-friendly, removable debris container, as these were known elements for improving the performance of cleaning robots.
  • Expectation of Success: The combination involved applying conventional and well-understood technologies. Integrating a known spring suspension (WO ’744) and a removable bin (Allen) into a base robot (Kirkpatrick) was a matter of applying known design principles with predictable results.

Ground 2: Claims 2-4 and 19 are obvious over Kirkpatrick in view of WO ’744, Allen, and further in view of Kraenzle.

• Prior Art Relied Upon: Kirkpatrick (Patent 6,481,515), WO ’744 (PCT application WO02067744A1), Allen (Patent 5,995,884), and Kraenzle (EP 0686371).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination in Ground 1 to address dependent claims requiring a second rotating member (e.g., a side brush). Petitioner asserted that Kraenzle explicitly disclosed a floor sweeper with a removable side brush mounted on a front corner of the housing to feed dust and material from walls and corners toward a central roller brush. This teaching was argued to directly meet the limitations of claims 2-4, which specify a second rotating member configured to cooperate with the first.
  • Motivation to Combine: A POSITA, having assembled the robot of Ground 1, would be motivated to improve its edge- and corner-cleaning performance. The use of side brushes for this purpose, as taught by Kraenzle, was a well-known solution in the field of floor sweepers. Adding a side brush to the base robot would have been a simple and predictable design choice to enhance overall cleaning efficacy.
  • Expectation of Success: The integration of a side brush was a routine modification in the art of cleaning robots. A POSITA would have had a high expectation of success in mounting a side brush, like that in Kraenzle, onto the robotic platform established by the other references.

Ground 4: Claims 1, 2-7, 9-10, and 17-19 are obvious over Waldhauser in view of Drunk, Allen, and further in view of Bryant.

• Prior Art Relied Upon: Waldhauser (Patent 4,380,844), Drunk (Patent 5,377,106), Allen (Patent 5,995,884), and Bryant (Patent 6,761,372).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner presented this as an alternative combination where Waldhauser provided the basic automatic floor cleaning machine with a propulsion system and brushes. Drunk was cited for its disclosure of a navigation and control system for an unmanned vehicle, including sensors to detect and react to obstacles, and programming for a meandering path to cover an entire surface. Allen again supplied the teaching of a removable debris bag. Bryant was introduced to teach a sophisticated vehicle suspension system using a spring between the chassis and wheel axle support to manage sprung weight, including a rebound control spring, which maps to the claimed spring-biased arm.
  • Motivation to Combine: A POSITA would have been motivated to combine the mechanical cleaning elements of Waldhauser with the advanced autonomous control systems of Drunk to create a fully autonomous robot. To improve ride quality and ensure constant floor contact, the POSITA would incorporate a known suspension system like Bryant's. For user convenience, the removable bin from Allen would be a natural addition.
  • Expectation of Success: Each reference provided a distinct, modular component of the claimed invention (mechanical platform, navigation, suspension, debris collection). Combining these known elements from their respective fields to create an improved autonomous cleaning robot would have been a predictable endeavor for a POSITA.
• Additional Grounds: Petitioner asserted Ground 3, an obviousness challenge to claims 1, 5-7, 9-10, and 17-18 over WO '744 in view of Allen.

4. Key Claim Construction Positions

• "arm": Petitioner argued that this term should be construed under the Broadest Reasonable Interpretation (BRI) standard as "a member that is movably mounted at one end, projecting from another structure." This broad construction was important for Petitioner’s argument that the motor-gearbox housing in Kirkpatrick and the drive wheel support in WO ’744 met the "arm" limitation, even if not explicitly labeled as such.
• "the weight of the floor cleaning robot overcomes a force": Petitioner contended this phrase means the robot's weight is sufficient to stress the spring/resilient member, causing the wheel to move from its fully extended position to a relatively retracted position when placed on the ground. This interpretation was central to applying prior art like WO ’744, which describes its robot's weight causing drive wheels to move from a resiliently extended to a partially retracted position.
• "spring": Petitioner argued that "spring" and "resilient member" are not limited by structure in the ’090 patent and should be interpreted as any type of resilient structure configured to restore to a default position or shape. This allowed Petitioner to apply prior art disclosing various resilient elements, such as the compression spring in Kirkpatrick and the coil spring in Bryant.

5. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-11 and 17-19 of the ’090 patent as unpatentable.